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本文以中国东北地区为对象,采用针对农业土壤碳库和痕量气体排放估算建立的反硝化分解(DNDC)模型,在建立有关中国东北地区气候、农业土壤和农业生产的分县数据库基础上,估算了中国东北地区农田土壤碳库储量,为1.27(0.92-1.62)GtC(1015g),平均为C63.57thm-2,是全国C平均值45.38thm-2的1.4倍,并发现东北地区农田土壤碳量有较明显的地区差异,东北部较高,西南部较低,从西南向东北方向土壤有机碳含量逐渐增加。经过一年的耕种后,农田土壤碳总的变化量为-22.97(-35.57—-10.37)TgC,变化率为-1.809%,C平均为-1.36thm-2,是全国C平均变化量-0.731thm-2的1.86倍,也有较明显的地区差异,北部减少幅度较大,西南部相对变化不大或有所增加。通过DNDC模型模拟研究发现我国东北地区经过耕种土壤碳损失量为0时,初始土壤有机质含量为18.3gkg-1。这点是土壤碳经过耕种后增加或减少的临界点。并通过情景分析,提出了增加东北地区农田土壤碳储量的措施。
Based on the analysis of DNDC model based on the estimation of agricultural soil carbon pool and trace gas emission in Northeast China, based on the sub-county database about the climate, agricultural soil and agricultural production in Northeast China, The soil carbon stocks in farmlands in northeast China were estimated to be 1.27 (0.92-1.62) GtC (1015g) with an average of C63.57thm-2, 1.4 times the national C average of 45.38thm-2. There are obvious regional differences in carbon content, northeast is higher, southwest is lower, soil organic carbon content increases from southwest to northeast. After one year’s cultivation, the total soil C change of farmland was -22.97 (-35.57-10.37) TgC, the change rate was -1.809%, C average was -1.36thm-2, which was the average change of C in the whole country -0.731 thm-2 1.86 times, there are more obvious regional differences in the larger decrease in the north, the relative little change in the southwest or increased. According to the DNDC model simulation study, we found that the initial soil organic matter content is 18.3gkg-1 when the carbon loss in cultivated soils in northeast China is 0. This is the critical point for soil carbon to increase or decrease after cultivation. Through scenario analysis, this paper puts forward measures to increase the soil carbon storage in farmland in Northeast China.